**2. Treatment of carotid stenosis**

Treatment options for carotid stenosis include medication or surgery [10-12]. Clinical treat‐ ment includes antiplatelet agents and statins associated with the control of risk factors such as arterial hypertension, dyslipidemia, hyperglycemia, diabetes, and smoking [13]. Relevant studies comparing the outcomes of clinical treatment and surgery showed an important

reduction in the risk of CVA among the patients selected for surgical treatment. In the NASCET study, the risk of CVA was significantly reduced by surgery (9% in the surgical group versus 26% in the medication treatment) [10]. In another classical trial with asymptomatic patients, surgical treatment was also associated with a better prognosis (4.8% versus 10.6% for medi‐ cation treatment) [14].

adverse effects occurred in more than 10% of patients within the short 30-day follow-up [27,28]. Subsequently, deformation was avoided using the self-expandable Wallstent® stent [29] and later by self-expandable nitinol alloy stents. However, the risk of cerebral embolism remained, although it was reduced compared with the risk associated with the first stents. Restenosis, which occurred frequently after angioplasties without a stent, was reduced drastically. Currently, all manufacturers of endovascular intervention materials produce stents with rapid self-expanding technology compatible with the thin 0.014-inch guides common to most cerebral protection systems [13]. Nonetheless, carotid stenosis treatment with either CAS with cerebral protection or with CEA continues to carry an inherent risk of

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**3. Is there a difference between materials used in carotid angioplasty?**

As the CREST Trial showed, the risk of ICVA in CAS is a technical problem that remains unsolved [12]. A heavily debated topic in the literature is the design of the metallic alloy used to outline the empty spaces, which are called cells. Different types of frames for the metal skeleton can promote plaque stabilization, depending on the size of the free area between the metal brackets. Stents with a braided metallic mesh, which are dense throughout, can be more effective at covering the plaque and reducing the risk of embolism [30]. These closed-cell stents are characterized by small cells (areas enclosed by metal) joined together (Figure 1). Segmental rings connected to each other by points that are welded together and large areas that are not covered by metal are called open-cell stents [30]. Hybrid stents, which have a closed-cell design in their central part and an open-cell design in their proximal and distal parts, can also be

There are several examples of closed-cell stents, such as Wallstent® (Boston Scientific), Xact® (Abbott), and NexStent® (Endotex). The Carotid Wallstent® is considered the prototype for closed-cell design stents. Examples of stents with an open-cell design include Protégé® (Ev3), Precise® (Cordis), Acculink® (Abbott), and Exponent® (Medtronic). The Carotid Wallstent® model is manufactured with a stainless steel alloy and a closed-cell mesh, which may help to prevent embolic complications. Because of its design, the Carotid Wallstent® (Boston Scien‐ tific) undergoes a shortening by approximately 30% [31], and caution must be used when estimating its length. The Precise® (Cordis) stent is a nickel and titanium alloy (nitinol®) mounted on rings, which promotes an open-cell aspect and offers great flexibility. The Protégé® (Ev3) stent also uses nitinol and an open-cell design, and both conical and straight versions are available. These last two stents cannot be collected after they begin to release; therefore, they should only be opened when the implant site is certain. However, these stents

A study by Tadros et al. used photomicroscopy to analyze debris found in the filters after CAS and showed that open-cell stents are associated with a larger mean particle size compared with

embolism.

found. These stents are rarely used in practice.

do not undergo shortening.

closed-cell stents [32].

The two main effective treatment options for patients with serious carotid stenosis are carotid endarterectomy (CEA) and carotid angioplasty with stent (CAS). CEA was the first surgical option developed. It is indicated for symptomatic patients with carotid stenosis >60% and in centers with surgical risk below 6%. In asymptomatic patients, a degree of stenosis >70% is considered an indication for surgical treatment, but surgeons must notice morbi-mortality lower than 3% [10,14-17].

The most recent surgical option is CAS, which consists of an approach to stenosis through a natural route within the vessels. A flexible guide wire and catheter are inserted into the arterial system through a peripheral venipuncture and are maneuvered to the stenosis site, where the narrow portion is opened using the stent and balloon dilation.

CAS is considered less invasive than traditional surgery (CEA) and does not require an incision on the lateral side of the cervical region [18]. CAS also has the advantages of being able to maintain a steady flow of blood to the brain during CAS with a filter, generally using local anesthesia, and allowing early hospital discharge [18]. Thus, the indications for CAS are the same as those for CEA and also encompass other situations, such as comorbidities, occlusion of the contralateral carotid artery, high carotid bifurcation, concomitant distally associated stenosis, postradiotherapy stenosis, and restenosis after carotid endarterectomy [9,19,20].

The CREST trial compared CAS and CEA, examining complications, such as CVA, myocardial infarction, or death during CAS and CEA, and CVA four years after these techniques were applied. The authors observed similar rates of complications between CAS and CEA and concluded that the techniques are equivalent in terms of short- and long-term clinical results, but CAS carries a higher risk of ICVA and CEA carries a higher risk of heart attack during the periprocedural period. This study also found that good results might be influenced by good treatment and the expertise of the interventionists and surgeons [12].

Currently, CAS is considered a safe and effective technique for treating stenosis in the carotid artery >70% in symptomatic patients, when assessed by noninvasive methods, and >50% when assessed by catheter angiography, as indicated by the guidelines of the American Stroke Association (ASA; Class I recommendation with evidence level B) [21].

The first angioplasty for carotid stenosis was performed by Mathis in 1979 in a patient with fibromuscular dysplasia that caused symptomatic carotid stenosis [22]. The first angioplasty for atherosclerotic lesions was reported in 1980 by Kerber et al. [23]. The first series of carotid angioplasties was published in 1987 by Theron et al. and included 11 patients [24]. At the beginning of the 1980s, publications regarding the use of balloon occlusion in the carotid artery to reduce embolic complications began to appear [24-26].

The first balloon-expandable stent was used in a carotid artery in 1989; however, these early stent models were prone to extrinsic compression and deformation. In this group of stents, adverse effects occurred in more than 10% of patients within the short 30-day follow-up [27,28]. Subsequently, deformation was avoided using the self-expandable Wallstent® stent [29] and later by self-expandable nitinol alloy stents. However, the risk of cerebral embolism remained, although it was reduced compared with the risk associated with the first stents. Restenosis, which occurred frequently after angioplasties without a stent, was reduced drastically. Currently, all manufacturers of endovascular intervention materials produce stents with rapid self-expanding technology compatible with the thin 0.014-inch guides common to most cerebral protection systems [13]. Nonetheless, carotid stenosis treatment with either CAS with cerebral protection or with CEA continues to carry an inherent risk of embolism.

reduction in the risk of CVA among the patients selected for surgical treatment. In the NASCET study, the risk of CVA was significantly reduced by surgery (9% in the surgical group versus 26% in the medication treatment) [10]. In another classical trial with asymptomatic patients, surgical treatment was also associated with a better prognosis (4.8% versus 10.6% for medi‐

The two main effective treatment options for patients with serious carotid stenosis are carotid endarterectomy (CEA) and carotid angioplasty with stent (CAS). CEA was the first surgical option developed. It is indicated for symptomatic patients with carotid stenosis >60% and in centers with surgical risk below 6%. In asymptomatic patients, a degree of stenosis >70% is considered an indication for surgical treatment, but surgeons must notice morbi-mortality

The most recent surgical option is CAS, which consists of an approach to stenosis through a natural route within the vessels. A flexible guide wire and catheter are inserted into the arterial system through a peripheral venipuncture and are maneuvered to the stenosis site, where the

CAS is considered less invasive than traditional surgery (CEA) and does not require an incision on the lateral side of the cervical region [18]. CAS also has the advantages of being able to maintain a steady flow of blood to the brain during CAS with a filter, generally using local anesthesia, and allowing early hospital discharge [18]. Thus, the indications for CAS are the same as those for CEA and also encompass other situations, such as comorbidities, occlusion of the contralateral carotid artery, high carotid bifurcation, concomitant distally associated stenosis, postradiotherapy stenosis, and restenosis after carotid endarterectomy [9,19,20]. The CREST trial compared CAS and CEA, examining complications, such as CVA, myocardial infarction, or death during CAS and CEA, and CVA four years after these techniques were applied. The authors observed similar rates of complications between CAS and CEA and concluded that the techniques are equivalent in terms of short- and long-term clinical results, but CAS carries a higher risk of ICVA and CEA carries a higher risk of heart attack during the periprocedural period. This study also found that good results might be influenced by good

Currently, CAS is considered a safe and effective technique for treating stenosis in the carotid artery >70% in symptomatic patients, when assessed by noninvasive methods, and >50% when assessed by catheter angiography, as indicated by the guidelines of the American Stroke

The first angioplasty for carotid stenosis was performed by Mathis in 1979 in a patient with fibromuscular dysplasia that caused symptomatic carotid stenosis [22]. The first angioplasty for atherosclerotic lesions was reported in 1980 by Kerber et al. [23]. The first series of carotid angioplasties was published in 1987 by Theron et al. and included 11 patients [24]. At the beginning of the 1980s, publications regarding the use of balloon occlusion in the carotid artery

The first balloon-expandable stent was used in a carotid artery in 1989; however, these early stent models were prone to extrinsic compression and deformation. In this group of stents,

narrow portion is opened using the stent and balloon dilation.

treatment and the expertise of the interventionists and surgeons [12].

Association (ASA; Class I recommendation with evidence level B) [21].

to reduce embolic complications began to appear [24-26].

cation treatment) [14].

150 Carotid Artery Disease - From Bench to Bedside and Beyond

lower than 3% [10,14-17].
